Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756352Ab2FODCv (ORCPT ); Thu, 14 Jun 2012 23:02:51 -0400 Received: from mail9.hitachi.co.jp ([133.145.228.44]:43568 "EHLO mail9.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754149Ab2FODCu (ORCPT ); Thu, 14 Jun 2012 23:02:50 -0400 X-AuditID: b753bd60-9a0f2ba000000f6c-f2-4fdaa5d77bfc X-AuditID: b753bd60-9a0f2ba000000f6c-f2-4fdaa5d77bfc Message-ID: <4FDAA5D5.7080606@hitachi.com> Date: Fri, 15 Jun 2012 12:02:45 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Andrew Morton , Frederic Weisbecker , yrl.pp-manager.tt@hitachi.com Subject: Re: [RFC][PATCH 02/13 v2] ftrace: Consolidate arch dependent functions with list function References: <20120612224327.426900129@goodmis.org> <20120612225424.495625483@goodmis.org> In-Reply-To: <20120612225424.495625483@goodmis.org> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1881 Lines: 47 (2012/06/13 7:43), Steven Rostedt wrote: > From: Steven Rostedt > > As the function tracer starts to get more features, the support for > theses features will spread out throughout the different architectures > over time. These features boil down to what each arch does in the > mcount trampoline (the ftrace_caller). > > Currently there's two features that are not the same throughout the > archs. > > 1) Support to stop function tracing before the callback > 2) passing of the ftrace ops > > Both of these require placing an indirect function to support the > features if the mcount trampoline does not. > > On a side note, for all architectures, when more than one callback > is registered to the function tracer, an intermediate 'list' function > is called by the mcount trampoline to iterate through the callbacks > that are registered. > > Instead of making a separate function for each of these features, > and requiring several indirect calls, just use the single 'list' function > as the intermediate, to handle all cases. If an arch does not support > the 'stop function tracing' or the passing of ftrace ops, just force > it to use the list function that will handle the features required. Ah, I see. so even if the arch doesn't support passing ftrace_ops in mcount trampoline, this ensures that the correct ftrace_ops should be passed to the handlers. Reviewed-by: Masami Hiramatsu Thank you, -- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/